1. Field of the Invention
This invention relates to a single-reel type tape cartridge for use with magnetic recording-reproducing apparatus (hereinafter called a xe2x80x9crecorderxe2x80x9d).
1. Prior Art
Japanese Patent Application Kokai No. 63-251983 discloses a single-reel type tape cartridge having a brake lock which applies the brake on the tape reel and releases it by upward and downward motion within a hub on which the tape is wound.
FIG. 6 is an exploded view of a single-reel type cartridge of the prior art. FIG. 7 is a cross sectional view showing essential parts of the cartridge. For easier reference the components are shown upside down. The cartridge comprises a housing composed of an upper casing 1 and a lower casing 2, and a single tape reel 3 on which a length of tape 14 is wound and which is turnably held within the housing.
Upper and lower casings 1, 2 are formed, respectively, with cutouts 12, 22 which are joined to provide an opening into which a leader block 18 is inserted so as to be drawn out by a drive member of a recorder.
Tape reel 3 consists integrally of a hub 32 formed in one piece with a lower flange 33. It is driven for rotation by a drive of a recorder that is inserted into the opening 20 of lower casing 2.
Hub 32 has a tooth-like part formed on its inner surface to be in mesh with a brake lock 5 so as to prevent unwanted turning of tape reel 3 when the latter is not in use.
Brake lock 5 has teeth 51 formed on its underside in mesh with the corresponding part of hub 32. Brake lock 5 is normally urged in the braking position by a brake spring 4.
A follower projection 52 of brake lock 5 has a recess 73 which slidably engages with a guide 13 formed on the inner surface of upper casing 1, allowing brake lock 5 to move up and down positively between a lower braking position and an upper brake release position.
A brake release projection 63 formed on the underside of brake lock 5 fits in a center hole 43 at the bottom of hub 32, and as soon as the cartridge is loaded in a recorder, brake release projection 63 is lifted with an attendant upward movement of brake lock 5 out of engagement with tape reel 3, setting the reel free to turn.
The beginning of tape 14 is wound round a pin member 8, which in turn is fixedly fitted in a pin-receiving groove of a leader block 18. When the cartridge is loaded in a recorder, leader block 18 is caught by a draw-out member that comes out of the recorder into an engaging recess 19 of the block. It is then drawn out, led along the tape path inside the recorder up to a take-up reel, and is eventually held within a recess formed in the periphery of the recorder""s take-up reel.
In the cartridge of the prior art, the brake on the hub is released as brake lock 5 is lifted with its brake release projection 63 pressed by a brake release member of a recorder. When the center of either projection 63 or the brake release member of a recorder is off the center of the other (a situation that can result from dimensional errors of the products), smooth release of the brake is sometimes impossible because the brake lock fails to move straightly upward or because the outer periphery of brake lock 5 catches a sloped rib 72 (FIG. 7) that aligns brake lock 5 to hub 32.
It might seem possible then to accomplish positive release of the brake by the interposition of a brake release plate between the brake release member of a recorder and brake lock 5 on the part of the cartridge. In that case the brake release plate would be deflected along its periphery because the latter is pushed upward while the center of the plate remains in contact with the brake button, leading to failure in positive release of the brake.
The present invention, therefore, aims at providing a brake plate structure capable of ensuring positive release of the brake plate.
The tape cartridge of the prior art prevents unwanted turning of the reel when the cartridge is not in use by pressing brake lock 5 downward by reel spring 4 and thereby keeping teeth of the reel in mesh with teeth 51 of the brake lock.
The brake lock mechanism for use in a tape cartridge of the character according to the invention, as will be explained later, includes a brake release plate having three legs and interposed between a reel hub and a brake lock, while the brake lock is urged downward by a spring member so that teeth of the reel and teeth of the brake lock are in mesh. When the tape cartridge is set in a recorder, drive means of the recorder engages the legs of the brake release plate and lowers the plate to a predetermined point where the teeth of the reel and brake lock are disengaged, whereby the reel is set free to turn and the tape is drawn out of the cartridge. At the time of cartridge assembling, three xe2x80x9cspiderxe2x80x9d legs of the brake release plate, inserted in advance in three corresponding holes formed in the reel hub, can sometimes come out of the holes in the course of assembling, making further assembling work impossible.
The present invention aims at facilitating the assembling of tape reels by minimizing the possibility of a brake release plate coming off from a reel hub with which it has been combined in advance as a subassembly.
The present invention solves the foregoing problems by providing a reinforcing structure between the center of main plate and legs of a brake release plate in a tape cartridge wherein a single tape reel on which a length of tape is wound is turnably held within a housing consisting of an upper casing and a lower casing, the lower casing having an opening through which a drive shaft of a recorder is to be inserted, the tape reel having a hub which is open at top and is closed at the bottom with a wall, the inner bottom wall of the hub having holes for engagement with a brake release plate, a metal disk is attached to the outer surface of the underside of said hub and teeth are formed on the outer surface around the metal disk for engagement with the drive shaft of a recorder, teeth to engage a brake lock are formed on the inner bottom surface of the hub, a brake release plate is mounted in the hub with legs fitted in the holes of the latter, a brake lock rests on the brake release plate, the brake lock having brake teeth formed on the periphery of the underside to be in mesh with the teeth of the hub and having a follower projection on the upper surface which is adapted to be guided by a guide projection formed in the upper casing so as to be movable upward and downward but not turnable, and a spring member is provided between the brake lock and upper casing to urge the brake lock in the braking position.
Preferably, the reinforcing structure comprises ribs extended, one for each, from the center of main plate to the legs.
Also preferably, a reinforcement is provided in a portion of the center of main plate surrounding the region where the brake release plate contacts the brake lock, said reinforcement being connected to the reinforcements extended to the legs.
The present invention provides a tape cartridge wherein a single tape reel on which a length of tape is wound is turnably held within a housing, the tape reel consisting of an upper flange, a lower flange, and a hub which is open at top and is closed at the bottom, the hub having a metal disk in the center of its outer bottom surface and having teeth formed on the outer bottom around the outer periphery the metal disk for engagement with a drive shaft of a recorder, the bottom of the hub having throughholes for engagement with a brake release plate, the hub having teeth formed on the inner side of the bottom to engage a brake lock, the brake release plate consisting of a main plate disposed between the brake lock and the inner surface of the hub and a plurality of legs adapted to fit in the throughholes in the bottom of the hub, the brake lock having brake teeth formed on the periphery of its underside and a contact area in the center for engagement with the brake release plate, the teeth of the hub and the brake teeth of the brake lock being in mesh to prevent unwanted turning of the tape reel, and a spring member is provided between the brake lock and an upper casing of the housing to urge the brake lock in the braking position, characterized in that each leg of the brake release plate has a short toe formed on its outer end to prevent the leg from coming off, out of engagement with, a corresponding hole of the hub.
The invention also provides a tape cartridge of the foregoing construction characterized in that each throughhole of the hub for engagement with the brake release plate is tapered on the inner side of the hub to facilitate the insertion of the toe of each corresponding leg of the brake release plate, and a small recess capable of accommodating the toe is formed on the outer side of the hub.
According to the invention, the efficiency of cartridge assembling is improved because there is no possibility of a once-incorporated brake release plate coming off from the hub during the course of assembling. Moreover, the brake release plate may be mounted in the hub in advance as a subassembly.